Optical Properties Of Doping Sr₂CeO₄Luminescent Material

In the thesis, we prepare Sr₂CeO₄:Eu³⁺、 Sr₂CeO₄:Ho³⁺ andSr₂CeO₄:Eu³⁺,Ho³⁺ phosphor by high-temperature solid state reactionand study the optical properties of the samples doped of themonatomic ions, the trivalent ions and other activator ions. ThroughX-ray diffraction （XRD）, scanning electron microscopy （SEM）, fieldemission scanning electron microscope （FESEM） andphotoluminescence spectrum （PL）, we characterize the productstructure, morphology and optical properties of the products ofpreparation. We also take a preliminary study about the light-emittingprinciple, and got some results as followed:First, we prepare Sr₂CeO₄:Eu³⁺and Sr₂CeO₄:Eu³⁺: A （A are the metalions） phosphor by high-temperature solid state reaction. The synthesisprocedure use the partial reaction, firstly annealed the power in the airat500°C for2h, then annealed at1200°C for6h, then we can get theSr₂CeO₄:Eu³⁺phosphor. The phosphor belongs to the triclinic system,which can absorb the200nm-400nm wavelength, and have goodlaunches at480nm,616nm. The experiments show that the dopedmetal ions can effectively improve the luminous intensity ofSr₂CeO₄:Eu³⁺phosphor. The experimental results show that the bestEu³⁺doped concentration is10%and the best calcination temperature is1200℃, and when Li+doped concentration is1%,the luminous intensityof Sr₂CeO₄:Eu³⁺phosphor has the most significantly improvement.Second, we prepare Sr₂CeO₄:Ho³⁺and Sr₂CeO₄:Ho³⁺: A （A are themetal ions） phosphor as the same method. Through testing thephosphor, we can find that the excitation peak is a broadband peakaround200nm-400nm, and its strongest peak is at280nm. The emissionpeak is a broadband peak, which has the strongest peak at480nm.Sr₂CeO₄:Ho³⁺has the highest luminous intensity at1200°C, andHo³⁺doped concentration is0.1%. The emission peak intensities are allimproved which are doped with different metal ions. When the Li+doped concentration is1%, the luminous intensity is the highest.Third, we prepare the Sr₂CeO₄:Eu³⁺, Ho³⁺phosphor for the first time.Through testing the phosphor, we can find the phosphor has threedistinct peaks at480nm,586nm and616nm. When the concentration ofEu³⁺is higher （10%）, the peak of480nm is gradually weakened, and thepeak of616nm is gradually increased with the Ho³⁺dopedconcentration increasing. When the concentration of Ho³⁺is1%, thepeak of616nm gets the highest. When the concentration of Eu³⁺is lower（2%）, the characteristic emission of Sr₂CeO₄and the peak of Eu³⁺are alldecreased, it can be indicated that the Ho³⁺ play as a quenching inthe phosphor.